Either of her first 2 albums are worthy recommendations. Listening to the US presses, they have quite decent recording quality for albums of that time ('87 & '89). More importantly, there is a bias towards acoustic instruments with synthesised music playing a background role. Also, for the first album, there are 2 wonderful piano+vocal pieces (Invisible Wall & Behind Closed Doors) and on Porcelain, theres 1 similar piece (Towerblock). These kinds of pieces are usually audiophile favourites as well. But more importantly, the albums all feature songs written by her, and they are really good. (though, she only seems to be able to write about love etc, so I'll have to mark her down for that).
The next album, Swept, is basically a disappointment containing very lightweight stuff. Listenable because of her voice, but nothing much else. Also, the sound quality is not that great, sounding very similar to Porcelain. After that, we have Falling Forward, which features improved sound quality, but tons of synthesisers and disappointing songs.
It was only in '97, when she released East West did she break out of this rut. Somehow, all the songs in the album are pretty good, and some are superb, like the title song, East West. Her voice has changed over 10 years, but its still a great voice, just different.